/*-
 *  * Copyright 2016 Skymind, Inc.
 *  *
 *  *    Licensed under the Apache License, Version 2.0 (the "License");
 *  *    you may not use this file except in compliance with the License.
 *  *    You may obtain a copy of the License at
 *  *
 *  *        http://www.apache.org/licenses/LICENSE-2.0
 *  *
 *  *    Unless required by applicable law or agreed to in writing, software
 *  *    distributed under the License is distributed on an "AS IS" BASIS,
 *  *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  *    See the License for the specific language governing permissions and
 *  *    limitations under the License.
 */

package org.datavec.api.io.serializers;

import java.io.IOException;
import java.io.InputStream;

/**
 * <p>
 * Provides a facility for deserializing objects of type <T> from an
 * {@link InputStream}.
 * </p>
 *
 * <p>
 * Deserializers are stateful, but must not buffer the input since
 * other producers may read from the input between calls to
 * {@link #deserialize(Object)}.
 * </p>
 * @param <T>
 */
public interface Deserializer<T> {
    /**
     * <p>Prepare the deserializer for reading.</p>
     */
    void open(InputStream in) throws IOException;

    /**
     * <p>
     * Deserialize the next object from the underlying input stream.
     * If the object <code>t</code> is non-null then this deserializer
     * <i>may</i> set its internal state to the next object read from the input
     * stream. Otherwise, if the object <code>t</code> is null a new
     * deserialized object will be created.
     * </p>
     * @return the deserialized object
     */
    T deserialize(T t) throws IOException;

    /**
     * <p>Close the underlying input stream and clear up any resources.</p>
     */
    void close() throws IOException;
}
